Abstract

The study aimed to investigate free light chain (FLC) monoclonality in patients with an abnormal free kappa/lambda ratio (FLC ratio). Seventy serum samples with abnormal FLC ratio were examined using an immunoturbidimetry (Binding Site, SPA) and the two different enzyme-linked immunosorbent assays (1. Sebia diagnostic kit; 2. in house methods), the monoclonal or oligoclonal bands of (FLC) by immunofixation electrophoresis (IE) and isoelectric focusing followed by affinity immunoblotting (IEF/AIB). The reference interval was calculated by non-parametric percentile method. 5.7% of samples examined by IE were suspected of monoclonal character of FLCs, but subsequently monoclonality was refuted by more sensitive IEF/AIB method; 7%, resp. 2.9% of samples showed FLC kappa, resp. FLC lambda oligoclonal character of bands. A statistically significant dependence was found between FLC ratio (Sebia) and FLC ratio (SPA), r_s = 0.510, p = .001. Kappa statistic evaluated a fair conformity between the FLC ratio (Sebia) and IEF/AIB (kappa = 0.468) and between FLC ratio (in house) and IEF/AIB (kappa = 0.300). The verified reference interval for FLC ratio (Binding Site) is between 0.35 and 2.18. The IEF/AIB is the most sensitive method to discriminate between monoclonal and oligoclonal bands of FLC. The Binding Site and Sebia diagnostic kits do not give consistent results. The Binding Site diagnostic kit provides more results above reference interval of FLC ratios. For routine decision on monoclonality of the FLC ratio (SPA) it is advisable to use a verified reference interval.

摘要

该研究旨在调查游离 kappa/λ 比率（FLC 比率）异常的患者的游离轻链 (FLC) 单克隆性。使用免疫比浊法（结合位点，SPA）和两种不同的酶联免疫吸附测定法（1. Sebia 诊断试剂盒；2. 内部方法）检查​​了 70 个具有异常 FLC 比率的血清样品，单克隆或寡克隆带（FLC）通过免疫固定电泳 (IE) 和等电聚焦，然后进行亲和免疫印迹 (IEF/AIB)。参考区间采用非参数百分位法计算。5.7% 的 IE 检测样本怀疑 FLC 具有单克隆性，但随后更灵敏的 IEF/AIB 方法驳斥了单克隆性；7%，分别为 2.9% 的样品显示 FLC kappa，分别为。条带的 FLC λ 寡克隆特征。_s = 0.510，p  = .001。Kappa 统计评估了 FLC 比率（Sebia）和 IEF/AIB（kappa = 0.468）之间以及 FLC 比率（内部）和 IEF/AIB（kappa = 0.300）之间的公平一致性。FLC 比率（结合位点）的验证参考区间介于 0.35 和 2.18 之间。IEF/AIB 是区分 FLC 单克隆和寡克隆条带的最灵敏方法。Binding Site 和 Sebia 诊断试剂盒的结果不一致。结合位点诊断试剂盒提供了高于 FLC 比率参考区间的更多结果。对于 FLC 比 (SPA) 单克隆性的常规决策，建议使用经过验证的参考区间。